normal change refers to changes that must follow the complete change management process.

By definition a normal change will proceed through all steps of the change management process and will eventually be reviewed by the Change Advisory Board (CAB).

The Normal change will break down into 3 subsideries

1- Minor(Change Manager approves rejects the change, schedules the change then reports action to CAB)
2- Major (As for the major and significant, RFC is usualy circulated through CAB(Board members when its significant) and the senior management/board level approves the changes.
3- Significant.

Just put in mind that ITIL is a best practice so makes sure its tailored to your requirements, dont go by the books, do whats right for the business.

Why not just describe to your client how the change process works and treat all words like "normal", "minor", "major" and "standard" as jargon, either not mentioning them at all, or at the appropriate moment saying "and we call that a X change" after describing it._________________"Method goes far to prevent trouble in business: for it makes the task easy, hinders confusion, saves abundance of time, and instructs those that have business depending, both what to do and what to hope."
William Penn 1644-1718